Rotary brush



` Feb. 13, 1940. G. R. CHURCHILL v 2,190,206'

ROTARY BRUSH Filed Nov. 1; 19:55

Il Ii Il Il lill)lll/lIIll/IIIIIIIIIII Ill;

, INVENTOR I I aux TroRNEY 'Patented Feb. 13, A1940 'UNITED STATES PATENT ori-ICE This invention relates to rotary brushes and particularly to rotary brushes for use in the industrial arts, for cleaning, polishing, coloring, finishing and burnishing metals and other materials. Rotary brushes when used for some kinds of work are rotated at speeds varying from 1700 revolutions per minute to 4000 revolutions per minute, at which speeds there is danger of the bristles being thrown out and disintegration of l0 the brush being effected by centrifugal force under conditions of use. v

The present'invention has for one of its objects to provide a rotary brush in which the bristles are so firmly secured as to enable the 18 brush to be rotated at substantially high speeds without dislodgment of the bristles or disintegration 'of the brush under 'conditions of use.

The invention further has for its object to provide a brush in which the density of the bristles is' I0 controllable, so that brushes most efficient or suitable for a particular kind of work may be made` by varying the density of the bristles. y

'Ihe invention also has for its object to produce 'a brush of the character described, which is inherently balanced, is waterproof, oil proof, and4 durable.

The invention is especially adapted for the production of rotary brushes employing non-metallic bristles such as Tampico, horsehair, china bristles and the like, and when bristles of this characterare employed a superior working surface may be obtained, in that the bristles may be firmly held at their butts and the free ends of the bristles be of like character so as to provide the rotary brush with a uniform working surface capable oi performing uniform and superior work for each kind of work for which 'the rotarybrush is made.

'I'hese and other features of this invention willV be hereinafter described and pointed out in the claim at the end of this specification. In the accompanying drawing: A liig.- 1 represents in elevation and section one f construction ofrotary brush embodying this invention.

45, Fig. 2, an end elevation of the rotary brush j shown in Fig. 1, with a portion of the end layer of bristles broknaway. and

Fig. 3, a longitudinal section of the rotary brush on a smaller scale and a portion of an apparatus i or bundles of bristles and overlap the reinforcing 50 50 with which the rotary brush may bemade. v

- In accordance with ythis invention, the rotary brush is provided with a plurality of rows or sections I0 of bristlesseparated from one another at s ,the inner orbutt portions I2 ofthe bristles by'4 one I6 or moreflayers or members I 8 of rubber or like Itis preferred to separate adjacent'rows or sec- I5 v tions Il of bristles by a layer or member I3. of rubber which is normally in an unvulcanized condition, and to heat the rubber layers or members I3 soas to render them soft or suiiiciently plastic to enable portions of the rubber layers to be coml0 pressed and forced into the bristles at or near their inner or butt ends, solthat when the rubber is vulcanized, the bristles of 'each row or section will be embedded in a rubber hub provided with a plurality of sockets' in which the rows of bristles u are iirmly held by the rubber and form with said hub a unitary structure,

The rowsor sections I0 of bristles are assembled upon a suitable mandrel or tube I 4 with their butt ends substantially close to the tube or mandrel, 20'

and as more or less space is left between the butt ends of the bristles and the-tube or mandrel', more or less of the rubber layers or members I3, when softened and compressed, will be forced between the bristles and the mandrel I l as well as into 26 the bristles, with the result that adjacent layers I3 of rubber are united and form a rubber hub having sockets in which the butts -of the rows of bristles are firmly held or set by the rubber.

I'he inner wall of the rubber hub is represented 30 by the heavy black line I5 in Figs. l and 2. It is preferred to use in the manufacture of the rotary brush a length or strip of bristles connected at their butt ends with means which not only tie the bunches or bristles together but also reinforce 36 them. One means for this purpose consists of a plurality of wires I6, herein shown as live in number, which are woven in such manner as to encompass and grip substantially equal bunches of bristles Il and form a strip of hunched bristles. 40

It is also preferred tov employ a strip 4or length of rubber-or the like of a width sufficient to cover I, the bristles from their butt ends to and .preferably wires II and, when cold, form lingers or keysv I1 between the bunches of bristles and reinforcing 1 members` for the weaving wires I 6, to resist breaking of rthe weaving wires under the influence' of centrifugal force at high speeds, and which also u resist movement of the bristles outward under the .influence of centrifugal force at high speeds. Y

wires and is less compressed than 'the portion of` the bristles with which the weaving wires are engaged, with the result 'that the bunches of bristles are provided with enlarged tapered or wedge-shaped butt end portions, which serve to assist in resisting movement of the bristles by centrifugal force.

'Ihe strips of bristles and rubber may be of such length as to form a plurality of rows of bristles and a plurality of rubber layers, and to simultaneously wind both strips about the mandrel or tube Il, so as to form a plurality of convolutions or annular rows of bristles separated at their butt portions by a plurality of convolutions or ring-'like members or layers of rubber` or like material which is initially thermo-plastic.

The strips of bristles and rubber are simultaneously wound upon the mandrel I4 and confined betweenheads 20, 2l, which may and preferably will be provided with devices, shown as pins 22', 23, for anchoring the free ends of .the strips after the manner shown in Fig. 3.

'I'he anchoring devices 22, 23 enable the rub- *Y ber strip and the strip of bristles to have their opposite ends located in such manner as to assist in balancing the brush.

The head 20 may be secured to themandrel I4 by one or more set screws 25 before the strips of bristles and rubber are wound upon the mandrel, and after the strips are wound thereon, the head 2l is placed on the mandrel and moved under pressure toward the stationary head 20, so as to subject the bristles and rubber to an initial compression, and.when so compressed the head 2| may be secured to the mandrel by one or more set screws 26 or otherwise.

a then subjected to heat below a temperature at whichJthe bristles will be burnt' or charred and for such length of time as will render the rubber relatively soft or plastic and in a condition in which by increasing the pressure it can be forced between the butt ends of the bristles and the'mandrel andinto the outside bristles ofeach bunch, so as to connect adjacent convolutions of rubber and form 'therubber hub having a plurality o f annular sockets extended 'mwardly from the outside of 'the hub, in which sockets are located a pluralityof rows of bristles which are set or rmly held in said sockets by the rubber against movement by centrifugal force under ,conditions of use. As stated above, the rubber strip is preferably made of sumcient width`to extend beyond the reinforcing wires Il, so that portions of the rubcompressed, heating of the rubber is resumed.'

and continued at a temperature below the point at which the bristles will char or burn, and for such length of time as will properly vulcanize the rubber.

After the rubber has been properly vulcanized,

the heat is withdrawn and the brush thus formed is allowed to cool, andwhen cooled, it is' removed from the mandrel and may and preferably will be provided-with a iinishing hub 30 and with anges or heads 3| of wood, ber, or any other desired material asshown in Figs. l and 2.

The temperatures to which the rubber and bristles are subjected may vary according to the A results in a gradient in hardness of the rubber strip which is a maximum at the butts of the bristles and decreasestowardthe outer side of the rubber strip.

In this manner, the rubber member between adjacent rows of bristles may be subjected at its outer edge' to a less heat than that necessary to vulcanize the rubber member at the butt ends ofthe bristles, with the result that the outer edge of the rubber strip may be slightly yielding to enable the bristles to bend and avoid being broken, especially when the brush is used on work in which lit is necessary for the operator to press the work against the rotating brush with considerable force.

It is also preferred to provide the butt ends of the bristles with a thin layer or coating of a material with which the rubber strip may bond or unite to more effectively bond or affix the bristles to the rubber. To this end the strip of bristles may have the butt side of the strip covered with a thin layer of rubber cement, shellac or like substance.

Itis preferred to Wind the bristles in the form of a strip as by so doing the rotary brush is pro-A vided with a plurality -of convolutions which are helically arranged on the brush, which helical arrangement prevents streaking on the surface of the work, especially on silver, steel, brass and like surfaces. t

It will be observed that a rotary brush having a working surface of any desired width within limits may be made by means of strips of bristles and rubber of a length greater than the circumference of the mandrel and the cost of production may'thus be materially reduced. The

strips of rubber'may be of any desired thickness.

form, it is not desired to limit the invention in this respect, as the bristles may be laid by hand upon the rubber layer on the mandrel or they :Bay be stapied or otherwise secured to the rub- It will also be observed that the-density of the working surface of the brush may be adjusted to the particular kind offwork which is to be performed by the brush. Some kinds of work require a brush in which the bristles are dense,

and other kinds require a brush in which the bristles are not so dense, and these conditions may be met by varying the number of bristles in the bunches and the thickness of the rubber layer for a given width "of brush.

It will further be observed that the butt ends of the bristles are embedded or set in a rubber v While it is preferred to use the bristles in strip hub, which renders the brush water and oil proof, and the bristles are permanently aflixed in the hub and dislodgment of the bristles or disintegration of. the brush by centrifugal force under 5 conditions of use is avoided.

'I'he free end of the stripsof bristles and rubber of greater length than the circumference of the mandrel may be secured before the head 2| is placed on the mandrel by a staple 35'or other 10 wise so as to prevent said strips from unwinding more or less while the head 2| is being placed on the mandrel. i

It is preferred to connect the bristles together by the weaving wires I6, butl it is not desired to 15 limit the invention in this respect, as they may be connectedl together by sewing or in any other suitable manner.

what is claimed is:

In a rotary brush adapted for high speed ro tation, an integral substantially cylindrical hub of vulcanized rubber having an axial aperture therethrough by which the hub. may be mounted for rotation, a plurality of bunches of bristles arranged in at least one row extending around said hub, each of said bunches extending substantially radially of sald'hub and having one end ex- A tending a substantial distance into said hub,

the rubber of said hub extending intov said bunches between the bristles thereof and actually between said bunches so that said end of each said bunch is embedded in the rubber ofsaid hub to secure the same against the action of centrifugal force under high speed rotation, the rubber of said hub being softer adjacent the periphery thereof than adjacent said aperture so as to cushion said bunches against circumferential Iorces.

` GEORGE RfcHuRcmLn. 

